1. Field of the Invention
The present invention relates to fiber lasers and amplifiers, and more specifically, it relates to a cladding pumped fiber amplifier capable of watt level output powers and that can amplify narrow band laser sources.
2. Description of Related Art
This fiber amplifier was developed as part of a sum frequency mixing laser system designed to generate 589 nm light for laser guide star applications at Lawrence Livermore National Laboratory. The other laser source at 1583 nm was constructed entirely of commercially available components. The 938 nm amplifier has required significant development to bring to realization. In the course of this development, the present inventors have created a novel device not previously described elsewhere. The goal is to achieve a compact reliable source of narrow bandwidth laser light at 938 nm with output powers exceeding 10 W.
Utilizing the Nd-doped optical fiber made with standard commercial techniques, the present inventors constructed a 938 nm optical fiber amplifier which achieved 2.1 W of output power at 938 nm with 20 W of coupled pump power at 800 nm and cooled to liquid nitrogen temperatures. This was the highest power 938 nm fiber amplifier constructed to date, but it is still inadequate for many important tasks. The present inventors have developed a higher power 938 nm amplifier that can be scaled to very high and which operates at room temperature.